Methods and systems for detecting staple cartridge misfire or failure

ABSTRACT

A surgical stapler system may include a surgical instrument comprising an end effector configured to receive a removable staple cartridge, and an actuation mechanism operably coupled to actuate the end effector to perform a stapling procedure. The surgical stapler system also may include a drive system operably coupled to transmit an actuation force to the actuation mechanism and a controller operably coupled to the drive system. The controller may be configured to measure an actuation force transmitted by the drive system to the actuation mechanism, and control continued transmission of the actuation force based on a comparison of the measured actuation force to a range defined from a minimum threshold actuation force to a maximum threshold actuation force.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/194,771, filed Jun. 28, 2016, now U.S. Pat. No. 10,213,202, which isa continuation of U.S. patent application Ser. No. 13/472,431, filed May15, 2012, now U.S. Pat. No. 9,393,017, which is a continuation-in-partof U.S. patent application Ser. No. 13/350,512, filed Jan. 13, 2012, nowU.S. Pat. No. 9,226,750, which claims the benefit of U.S. ProvisionalPatent Application No. 61/443,148, filed Feb. 15, 2011, each of which isincorporated herein by reference in its entirety.

The present application is related to U.S. Provisional Application No.61/551,880, entitled “Cartridge Status and Presence Detection,” filed onOct. 26, 2011; U.S. Provisional Application No. 61/560,213 entitled“Cartridge Status and Presence Detection,” filed on Nov. 15, 2011; U.S.application Ser. No. 12/945,541 entitled “End Effector with RedundantClosing Mechanisms,” filed on Nov. 12, 2010; U.S. ProvisionalApplication No. 61/260,907, entitled “END EFFECTOR WITH REDUNDANTCLOSING MECHANISMS,” filed on Nov. 13, 2009; U.S. ProvisionalApplication No. 61/260,903, entitled “WRIST ARTICULATION BY LINKEDTENSION MEMBERS,” filed on Nov. 13, 2009; U.S. Provisional ApplicationNo. 61/260,915, entitled “SURGICAL TOOL WITH A TWO DEGREE OF FREEDOMWRIST,” filed on Nov. 13, 2009; and U.S. Provisional Application No.61/260,919, entitled “MOTOR INTERFACE FOR PARALLEL DRIVE SHAFTS WITHINAN INDEPENDENTLY ROTATING MEMBER,” filed on Nov. 13, 2009; each of whichis incorporated herein by reference in its entirety.

INTRODUCTION

Minimally invasive surgical techniques are aimed at reducing the amountof extraneous tissue that is damaged during diagnostic or surgicalprocedures, thereby reducing patient recovery time, discomfort, anddeleterious side effects. As a consequence, the average length of ahospital stay for standard surgery may be shortened significantly usingminimally invasive. A common form of minimally invasive surgery isendoscopy, and a common form of endoscopy is laparoscopy, which isminimally invasive inspection and surgery inside the abdominal cavity.In standard laparoscopic surgery, a patient's abdomen is insufflatedwith gas, and cannula sleeves are passed through small (approximatelyone-half inch or less) incisions to provide entry ports for laparoscopicinstruments.

Laparoscopic surgical instruments generally include an endoscope (e.g.,laparoscope) for viewing the surgical field and tools for working at thesurgical site. The working tools are typically similar to those used inconventional (open) surgery, except that the working end or end effectorof each tool is separated from its handle by an extension tube (alsoknown as, e.g., an instrument shaft or a main shaft). The end effectorcan include, for example, a clamp, grasper, scissor, stapler, cauterytool, linear cutter, or needle holder.

To perform surgical procedures, the surgeon passes working tools throughcannula sleeves to an internal surgical site and manipulates them fromoutside the abdomen. The surgeon views the procedure by means of amonitor that displays an image of the surgical site taken from theendoscope. Similar endoscopic techniques are employed in, for example,arthroscopy, retroperitoneoscopy, pelviscopy, nephroscopy, cystoscopy,cisternoscopy, sinoscopy, hysteroscopy, urethroscopy, and the like.

Minimally invasive telesurgical robotic systems are being developed toincrease a surgeon's dexterity when working on an internal surgicalsite, as well as to allow a surgeon to operate on a patient from aremote location (outside the sterile field). In a telesurgery system,the surgeon is often provided with an image of the surgical site at acontrol console. While viewing an image of the surgical site on asuitable viewer or display, the surgeon performs the surgical procedureson the patient by manipulating master input or control devices of thecontrol console. Each of the master input devices controls the motion ofa servo-mechanically actuated/articulated surgical instrument. Duringthe surgical procedure, the telesurgical system can provide mechanicalactuation and control of a variety of surgical instruments or toolshaving end effectors that perform various functions for the surgeon, forexample, holding or driving a needle, grasping a blood vessel,dissecting tissue, or the like, in response to manipulation of themaster input devices.

Non-robotic linear clamping, cutting and stapling devices have beenemployed in many different surgical procedures. For example, such adevice can be used to resect a cancerous or anomalous tissue from agastro-intestinal tract. Unfortunately, many known surgical devices,including known linear clamping, cutting and stapling devices, haveopposing jaws that may generate less than a desired clamping force,which may reduce the effectiveness of the surgical device. Devices havebeen developed generating higher levels of clamping forces forapplicable surgical procedures (e.g., tissue stapling), however,clamping with high force jaws periodically fails. Additionally, firingof staples to seal tissue may fail. Detecting failure in clamping orfiring of a staple has proven difficult in some minimally invasivesurgical applications, however, since a surgeon may not have a clearview of the tissue being clamped or stapled and a tool inserted into abody is constrained by significant size and space limitations. Since asurgeon's tactile feedback in a robotic system can be somewhat limited,a surgeon may not realize when failure has occurred until after theclamping or firing procedure is complete.

In light of the above, it would be desirable to enable a surgeon todetect clamping or staple firing failure at the time it occurs, so thatthe procedure can be suspended or modified to reduce the likelihood oftissue damage and/or to allow the surgeon to mitigate the effects of anytissue which has been damaged. Given the limitations associated with aminimally invasive surgical environment, it would be desirable to detectfailure from outside the body without substantially adding to theprofile of the end effector.

Thus, methods and system which can detect failure and indicate failureto the user, yet are compatible with the demands of minimally invasiveprocedures are desirable. Such tools may be beneficial in surgicalapplications, particularly in minimally invasive surgical applications.

SUMMARY

Improved systems and methods to detect and indicate clamping and/orstaple firing failure are provided. The claimed methods and systemsrelate to detecting whether clamping of a material grasped between jawsor firing of a staple into the clamped material is likely to fail. Theclaimed systems and methods may detect failure in clamping or firingduring the process of clamping or firing, thereby reducing the potentialfor tissue damage from continuing to clamp or fire a staple afterfailure has occurred. The claimed systems and methods are particularlyuseful in surgical applications involving clamping of a body tissuebetween two jaws of an end effector and firing of a staple into theclamped tissue. Many surgical applications require clamping of a bodytissue at a clamping force sufficient for cutting, sealing and/orstapling of the clamped tissue. Since clamping and firing of a staplemay require relatively higher forces than tissue manipulation, failurein clamping or firing may potentially cause damage to the delicatetissues. The present methods and systems are particularly advantageousin minimally invasive surgical applications as they indicate failure assoon as it occurs and allows for detection of failure from outside thebody. While the various embodiments disclosed herein are primarilydescribed with regard to surgical applications, these surgicalapplications are merely example applications, and the disclosed endeffectors, tools, and methods can be used in other suitableapplications, both inside and outside a human body, as well as innon-surgical applications.

In a first aspect, the teachings provide a method of detecting failurein clamping of a material between jaws driven by an actuator, such as amotor or detecting failure in firing of staple, the firing force beingdriven by an actuator, such as a motor. The method includes monitoring adrive parameter of the actuator or motor during application of aclamping or firing force and, in response to the monitored driveparameter, outputting an indication on a user interface of clamping orfiring failure. Typically, an indication of clamping or firing failureoccurs when the monitored drive parameter of the actuator, such as atorque output of a motor or displacement of a driving mechanism, isoutside an acceptable range of drive parameters. The indication may alsobe indicative of a likelihood of clamping or firing failure, wherein thelikelihood of failure falls within a gradient between a first and secondlikelihood, the first likelihood being likely failure and the secondlikelihood being likely success. In many embodiments, the materialclamped and stapled is a body tissue, including an outer skin orinternal organs, such as a bowel, stomach or lung.

In accordance with the present teachings, various exemplary methods andsystems disclosed herein include monitoring a drive parameter duringclamping between a first and second jaw of an end effector or duringfiring of a staple into clamped tissue. Often, the clamped tissue is cutafter opposing sides of the tissue along the cutting line are stapled byone or more rows of surgical staples to seal the tissue. The endeffector is generally part of a minimally invasive robotic surgicalsystem. The clamp may include first and second jaws that may comprisetwo separate jaws or a first jaw articulable against a portion of theend effector, in which case the portion of the end effector comprisesthe second jaw. In one aspect, the methods include clamping of amaterial between the first and second jaw of an end effector or firingof a staple into the clamped material, typically in response to acommand from a user to clamp or fire. The system effects clamping orfiring by applying a force to a clamping mechanism and/or a force toform a staple. As the clamping or firing occurs, the system monitors thedrive parameter of the actuator applying the force to clamp or fire. Inresponse to the monitored drive parameter, the system outputs anindication on a user interface of clamping or firing progress, failureor success.

In many exemplary embodiments in accordance with present teachings, anindication of likely clamping or firing failure is provided in responseto the monitored drive parameter being outside an acceptable range ofdesired drive parameters of the actuator, such as a range of torqueoutputs. Often, the acceptable range of drive parameters vary with thedisplacement and/or the position and/or the velocity of the actuator ormotor, such that the acceptable range of drive parameters may bedifferent depending on the configuration of the end effector. Forexample, the acceptable range of drive parameters at an initialdisplacement of the actuator or motor (as the clamp starts from an openconfiguration) may be different from the acceptable range of driveparameters at a final displacement (such as when the jaw is in aclosed/clamped configuration). The same is true for the differentinitial configuration and final configuration of the firing mechanism.The system may detect the configuration of the end effector by sensingthe displacement or position of the actuator effecting movement, or themechanism through which the actuator effects clamping or firing.Configuration of the end effector also may be detected by communicationbetween a replaceable staple cartridge and a robotic interface. Examplesof such configuration detection are discussed in U.S. ProvisionalApplication No. 61/551,880, entitled “Cartridge Status and PresenceDetection,” filed on Oct. 26, 2011, and U.S. Provisional Application No.61/560,213 entitled “Cartridge Status and Presence Detection,” filed onNov. 15, 2011, the entire contents of each of which is incorporatedherein by reference. The clamping or firing is effected by the driveparameter through one or more mechanisms coupling the actuator to theend effector and/or the staple. The mechanism(s) may include a cable, ahypotube, a gear, or a lead screw. In many embodiments, the indicationof likely clamping failure is a visual indicator shown on a display of auser interface, but also may be communicated to the user by an audiosignal, visual signal, or other sensory indicator.

In accordance with another aspect of the present teachings, exemplarymethods of controlling a surgical stapler system are disclosed. Suchexemplary methods include monitoring an initial actuation force appliedto a stapler cartridge of the surgical stapler system and comparing theinitial actuation force to a threshold actuation force. Continuedapplication of actuation force to the cartridge is based on thecomparison. A threshold force greater than the initial actuation forceprovides an indication of cartridge misfire or failure, and a staplefiring sequence may be terminated in response to such a determination.The initial actuation force and the threshold force may be linearforces, or rotary forces (torques), applied to the cartridge by a drivesystem of the surgical stapler system. In response to a determinationthat a cartridge misfire or failure is occurring, the system outputs anindication on a user interface of cartridge misfire or failure and thefiring sequence is terminated. Subsequent to the comparison of theinitial actuation force to the threshold actuation force, the continuingactuation force applied during the remainder of the stapling sequence.Such monitoring compares the continuing actuation force to a minimumthreshold and a maximum threshold. A continuing actuation force belowthe minimum threshold or above the maximum threshold provides anindication of cartridge misfire or failure, and the staple firingsequence may be terminated in response to such a determination.

According to one aspect of the disclosure, a surgical stapler system inaccordance with the present teachings includes an end effector having aportion that removably receives a staple cartridge, a drive system thatapplies an initial actuation force to the staple cartridge, and a sensorfor measuring the initial actuation force applied to the staplecartridge. A controller is communicatively coupled to the sensor and thedrive system to receive a signal indicative of the initial actuationforce applied to the staple cartridge and to control a staple firingsequence based on a comparison of the initial actuation force and athreshold actuation force. In response to a determination that acartridge misfire or failure is occurring, the system outputs anindication on a user interface of cartridge misfire or failure. Inresponse to a determination that a cartridge misfire or failure isoccurring, the system terminates a staple firing sequence. Subsequent tothe initiation of the firing sequence, the controller continues toreceive a signal indicative of the actuation force as the firingsequence progresses (the measured actuation force). The controllercompares the measured actuation force to a minimum threshold force and amaximum threshold force. If the controller determines that the measuredactuation force falls below the minimum threshold force or exceeds themaximum threshold force, the controller may terminate the staple firingsequence.

In accordance with another aspect of the present teachings, an exemplarymethod or system may suspend driving of the actuator in response to anindication of failure or likely failure in clamping or firing of thestaple. The methods may also include maintaining a driving parameterafter an indication of failure, or maintaining a driving parameterdriving clamping while suspending a force driving firing of a staple. Inmany embodiments, the clamping mechanism is non-back driveable such thatno input is needed to maintain the clamping force once it is applied orestablished. In such cases, an input may be needed to unclamp andreverse the motion of the lead screw. The methods may include reversinga driving force so as to unclamp after outputting the indication offailure.

In accordance with the present teachings, exemplary embodiments of asystem include an end effector, a sensor, and a user interface. A firstand second jaw of the end effector are coupled to an actuator such thatdriving the actuator produces a clamping force so as to clamp a materialbetween the first and second jaws. The system may also include anactuator, such as a motor, releasably coupled to a stapling cartridgesuch that driving the actuator produces a firing force so as to fire thestaple through the clamped material and forming it into a closed shape.The clamping and firing actuator may be a single actuator or may beseparate actuators. The system may include a sensor for monitoring thedrive parameters applying the clamping or firing forces to the endeffector. The sensor may be a separate sensor or may be incorporatedinto the robotic surgical system and may also monitor a displacement ofthe motor or mechanism. The systems may also include a processor forcomparing the monitored drive parameter with a desired drive parameteror range of parameters. The processor may also determine the range ofacceptable drive parameters for a given displacement.

The system may comprise a first and second actuation mechanism foreffecting clamping and firing, respectively. The first and secondactuation mechanisms can employ different force transmission mechanismscorresponding with the force requirements for the clamping mode and thefiring force mode. For example, a force used by the first jaw actuationmechanism to move the jaw from the open to the close position caninclude a linear force or a torque (rotational force), and a force usedby the second jaw actuation mechanism to fire a staple through thetissue can include a linear force or a torque. In many embodiments, thefirst actuation mechanism includes a lead screw-driven mechanism for usein the high force clamping mode, and the second actuation mechanismincludes a second lead screw-driven mechanism for use in the firing ofthe staple. Alternatively, the clamping and firing may utilize a portionof or the same mechanism.

For a fuller understanding of the nature and advantages of the presentteachings, reference should be made to the ensuing detailed descriptionand accompanying drawings. Other aspects, objects and advantages of thepresent teachings will be apparent from the drawings and detaileddescription that follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a minimally invasive robotic surgery systembeing used to perform a surgery, in accordance with many embodiments.

FIG. 2 is a perspective view of a surgeon's control console for arobotic surgery system, in accordance with many embodiments.

FIG. 3 is a perspective view of a robotic surgery system electronicscart, in accordance with many embodiments.

FIG. 4 diagrammatically illustrates a robotic surgery system, inaccordance with many embodiments.

FIG. 5A is a front view of a patient side cart (surgical robot) of arobotic surgery system, in accordance with many embodiments.

FIG. 5B is a front view of a robotic surgery tool.

FIG. 6A is a perspective view of an end effector having an articulatedjaw, in accordance with many embodiments.

FIG. 6B is a perspective view of the end effector of FIG. 6A (with thearticulated jaw removed to better illustrate lead screw actuationmechanism components), in accordance with many embodiments.

FIGS. 7A and 7B illustrate components of a lead screw actuationmechanism, in accordance with many embodiments.

FIG. 8A illustrates components of a cable actuation mechanism, inaccordance with many embodiments.

FIG. 8B is a perspective view of the end effector of FIG. 8A with aportion of the articulated jaw removed to show cable actuation mechanismcomponents disposed behind the articulated jaw, in accordance with manyembodiments.

FIGS. 8C through 8F illustrate opposite side components of the cableactuation mechanism of FIG. 8A.

FIG. 9A is a perspective view illustrating a cable actuation mechanism,showing a cable used to articulate the jaw towards a clampedconfiguration, in accordance with many embodiments.

FIG. 9B is a perspective view illustrating the cable actuation mechanismof FIG. 9A, showing a cable used to articulate the jaw towards an openconfiguration.

FIG. 10 is a cross-sectional view illustrating components of a leadscrew actuation mechanism, in accordance with many embodiments.

FIG. 11 is a simplified diagrammatic illustration of a tool assembly, inaccordance with many embodiments.

FIG. 12 is a simplified diagrammatic illustration of a robotic toolmounted to a robotic tool manipulator, in accordance with manyembodiments.

FIG. 13 is a diagrammatic view of a telerobotic surgical system, inaccordance with many embodiments.

FIGS. 14A-14B illustrate the user interface assembly having a clampingfailure indicator, in accordance with many embodiments.

FIGS. 15A-15B illustrate examples of indicators of clamping failureindicators, in accordance with many embodiments.

FIGS. 16A-16B illustrates exemplary motor torques during clamping ascompared to a range of acceptable motor torques which vary with motordisplacement, in accordance with many embodiments.

FIG. 16C illustrates exemplary minimum and maximum threshold torquescompared to a measured actuation torque during a staple firing sequence,in accordance with the present teachings.

FIGS. 17-20 illustrate methods, in accordance with many embodiments.

FIGS. 21-22 illustrate flow charts utilizing methods in accordance withmany embodiments.

DETAILED DESCRIPTION

Improved systems and methods related to clamping and/or fastener firingare provided. The present teachings relate to providing an indicator ofwhether clamping of a given material fails during clamping. Theteachings may be used in systems having jaw members for clamping amaterial or firing of a staple into a clamped material. The claimedsystem and methods are particularly useful for minimally invasivesurgical applications, as they allow for failure detection inconstrained environments from outside the body. Such systems ofteninclude end effectors having jaws that clamp a body tissue and fire astaple into the tissue at a relatively high force. Clamping at a highclamping force allows the user to perform various procedures requiring ahard clamp. For example, a physician may require a hard clamp of bodytissues before cutting, sealing or stapling of tissue. Firing of staplesor other fasteners may also require use of relatively high forces todrive the staple through the body tissue and form the staple. Sinceclamping and staple firing utilize relatively high forces applied in aconfined surgical area, clamping or firing failure has the potential todamage delicate tissues. Additionally, stapling cartridges used insurgical stapling procedures may include a knife for cutting tissuebetween stapled areas. If the stapling system fails or misfires, suchthat staples are not deployed but the knife is deployed to cut thetarget tissue, tissue damage may occur.

Methods and systems in accordance with the present teachings areadvantageous as they allow detection of clamping or firing failureduring the clamping or firing process from outside the body withoutincreasing the profile of the end effector. Such methods and systemsallow for increased capabilities and safety for the patient whilemaintaining the reduced scale of the minimally invasive surgical tools.While the various embodiments disclosed herein are primarily describedwith regard to surgical applications, these surgical applications aremerely example applications, and the disclosed systems and methods canbe used in other suitable applications, both inside and outside a humanbody, as well as in non-surgical applications.

Typically, a system utilizing the present teachings includes an endeffector having two jaws for clamping a material and/or firing a stapleor fastener through the clamped material. The two jaws may comprise anarticulated jaw attached to an end effector, such that moving thearticulated jaw towards a portion of the end effector, the second jawbeing that portion of the end effector. In many embodiments, the systemuses two independent mechanisms to articulate the jaws of the endeffector. A first actuation mechanism provides a fast response/low forcemode that varies the position of the articulated jaw between a closed(grasped) configuration and an open configuration. In many embodiments,the first actuation mechanism is back-drivable. For example, in the lowforce grasping mode, the first actuation mechanism can be designed toprovide, for example, 5 pounds of clamping force between the tips of thefirst and second jaw. A second actuation mechanism provides a high forceclamping mode for clamping the body tissue between the jaws at thehigher clamping force. Often, the second actuation mechanism isnon-back-drivable. The second actuation mechanism often converts arelatively weak force or torque (but with large displacement available)to a relatively high force, closing the jaw of the end effector. Thesecond actuation mechanism can be designed to provide, for example, 50pounds of clamping force between the tips of the clamped jaws.

Typically, in applications using various exemplary methods in accordancewith the present disclosure, a surgeon clamps the body tissue at therelatively high clamping force and once clamped, fires a series ofstaples through the clamped tissue thereby sealing the tissue. If thejaws should fail to clamp completely, the resulting stapling and cuttingmay not provide adequate mechanical sealing of the tissue. Clampingforce is related to the characteristics of the material, such as tissue,being clamped. Also relevant is the starting thickness of the materialbeing clamped, its compressibility, and the size or area of the materialbeing clamped. Clamping of the tissue may fail for a variety of reasons,including too much tissue being grasped or insufficient tissue graspedbetween the jaws, including interference from an adjacent tissue, suchas a bone, or slippage of the tissue from between the jaws. Even ifclamping is successful, firing of a staple or other fastener may failfor a variety of reasons, including, for example, inadvertent reuse of apreviously fired cartridge, missing staples, a jammed staple,inconsistencies in the material, interference from another material, orslippage of the clamped material. The staple firing force may bedetermined by the staple geometry and material from which the staple isformed. Wire diameter, staple leg length, and sharpness of the stapletip may factor into firing force. The highest force is seen just priorto the initial bending of the staple leg after it has penetrated thecompressed material (tissue). This is referred to as the buckling load.

Therefore, it would be advantageous for systems and methods that candetect when clamping or firing failure occurs during the process ofclamping or firing and indicate such failure to a physician, therebyreducing the likelihood that tissue damage will result. Ways in whichtissue damage can be avoided by use of the claimed methods, include:terminating the clamping or firing process or allowing the user toterminate or modify the process after failure has been indicated oradvance warning of a firing failure before the material in the jaws isunclamped and released. The described systems and methods detect suchfailures and provide an indication to the user of failure or likelyfailure during clamping and/or staple firing into a clamped material.Clamping may be considered successful when in the clamped position, thedistance between the jaws are sufficient for performing a therapy, suchas firing a staple through the clamped tissue. This distance may varyaccording to various factors, including the type of tissue, type oftreatment, or the dimensions of a staple to be fired through the clampedtissue. In one aspect, the claimed methods and systems detect failure bymonitoring one or more drive parameters of an actuator or motor thatdrives the clamping and/or staple firing. In at least one embodiment,the motor provides a drive parameter or force output, such as a torque,to a mechanism so as to effect clamping and/or firing of a staple withthe end effector. The system may determine whether the drive parameteris within an acceptable range of desired drive parameters. Theacceptable range of drive parameters may vary according to thedisplacement, position, or velocity of the motor or the mechanismeffecting movement. Typically, if clamping or firing fails, the forceoutput of the driving motor drops below a minimum acceptable or lowerthreshold force, such as from an absence of material between clampingjaws, or the force output may spike above a maximum acceptable or upperthreshold force, such as from clamping on a bone or jamming of themechanism. Continuing driving of the motor in either case may result indamage to surrounding materials or tissue or to the motor or systemitself. By monitoring the force output of the driving motor duringclamping of the material and/or firing into the tissue, the claimedmethods and systems detect failure or likely failure during clamping orfiring and output an indication of such failure or likely failure to theuser. Additionally, the system and methods may automatically terminatethe clamping or firing or wait for further input from the user afterproviding an indication of failure. Ideally, the methods includemonitoring a drive parameter.

Minimally Invasive Robotic Surgery

Referring now to the drawings, in which like reference numeralsrepresent like parts throughout the several views, FIG. 1 is a plan viewillustration of an embodiment of the present teachings. FIG. 1illustrates a Minimally Invasive Robotic Surgical (MIRS) system 10,typically used for performing a minimally invasive diagnostic orsurgical procedure on a Patient 12 who is lying down on an Operatingtable 14. The system can include a Surgeon's Console 16 for use by aSurgeon 18 during the procedure. One or more Assistants 20 may alsoparticipate in the procedure. The MIRS system 10 can further include aPatient Side Cart 22 (surgical robot), and an Electronics Cart 24. ThePatient Side Cart 22 can manipulate at least one removably coupled toolassembly 26 (hereinafter simply referred to as a “tool”) through aminimally invasive incision in the body of the Patient 12 while theSurgeon 18 views the surgical site through the Console 16. Tool assembly26 includes end effector 25, the end effector having jaws for clampingthe tissue and a mechanism for firing a staple through the clampedtissue. An image of the surgical site can be obtained by an endoscope28, such as a stereoscopic endoscope, which can be manipulated by thePatient Side Cart 22 so as to orient the endoscope 28. The ElectronicsCart 24 can be used to process the images of the surgical site forsubsequent display to the Surgeon 18 through the Surgeon's Console 16.Electronics Cart 24 includes a Processor 27 for monitoring the driveparameter provided by the motor output to the end effector. Processor 27may monitor the drive parameter by comparing the drive parameter to anacceptable range of drive parameters. As the acceptable range of driveparameters may vary with the displacement, position, or velocity of theactuator or the mechanism effecting movement of the end effector, theProcessor 27 may also receive displacement data as to the displacementof the actuator or the end effector mechanism during clamping and/orfiring such that Processor 27 compares the monitored drive parametersagainst a range of acceptable drive parameters for any givendisplacement, position, or velocity. The displacement data may bemeasured directly or may be determined from positional data, orderivatives thereof, obtained by the robotic system, such as a roboticpatient-side manipulator (PSM) system, for example, described in U.S.Patent Application Publication No 2007/0005045, the entire contents ofwhich are incorporated herein by reference. In response to the monitoreddrive parameter, Processor 27 may output a clamping failure indicationto a user interface. The system 10 then communicates an indicator of theprediction to the physician on the Surgeon's Console 16 so as tocommunicate to the surgeon whether clamping or firing has failed.

FIG. 2 is a perspective view of the Surgeon's Console 16. The Surgeon'sConsole 16 includes a left eye display 32 and a right eye display 34 forpresenting the Surgeon 18 with a coordinated stereo view of the surgicalsite that enables depth perception. The Console 16 further includes oneor more input control devices 36, which in turn cause the Patient SideCart 22 (shown in FIG. 1) to manipulate one or more tools. The inputcontrol devices 36 will provide the same degrees of freedom as theirassociated tools 26 (shown in FIG. 1) so as to provide the Surgeon withtelepresence, or the perception that the input control devices 36 areintegral with the tools 26 so that the Surgeon has a strong sense ofdirectly controlling the tools 26. To this end, position, force, andtactile feedback sensors (not shown) may be employed to transmitposition, force, and tactile sensations from the tools 26 back to theSurgeon's hands through the input control devices 36.

The Surgeon's Console 16 is usually located in the same room as thepatient so that the Surgeon may directly monitor the procedure, bephysically present if necessary, and speak to an Assistant directlyrather than over the telephone or other communication medium. However,the Surgeon can be located in a different room, a completely differentbuilding, or other remote location from the Patient allowing for remotesurgical procedures (i.e., operating from outside the sterile field).

FIG. 3 is a perspective view of the Electronics Cart 24. The ElectronicsCart 24 can be coupled with the endoscope 28 and can include Processor27 to monitor the drive parameter and to determine an indication ofclamping failure in response to the monitored drive parameter. Processor27 may also process captured images for subsequent display, such as to aSurgeon on the Surgeon's Console, or on any other suitable displaylocated locally and/or remotely.

FIG. 4 diagrammatically illustrates a robotic surgery system 50 (such asMIRS system 10 of FIG. 1), in which the Processor 58 and Display 60 aredepicted separately from Electronics Cart 56 and Surgeon's Console 52.As discussed above, a Surgeon's Console 52 (such as Surgeon's Console 16in FIG. 1) can be used by a Surgeon to control a Patient Side Cart(Surgical Robot) 54 (such as Patent Side Cart 22 in FIG. 1) during aminimally invasive procedure. In preparation for firing a staple to seala body tissue, the Surgeon can command the tool of the Patient Side Cart54 to clamp between jaw members of an end effector. In response to thiscommand, Processor 58 can command the system to begin driving the motorto engage a mechanism that begins moving the jaws together and increasea clamping force to a desired clamping force. As the jaws begin movingtogether and the clamping force increases, the Processor 58 continuouslymonitors one or more drive parameters of the motor and compares thedrive parameters to an acceptable range of drive parameters as the motordrives the jaws to clamp at a desired clamping force. If at any pointduring clamping, the drive parameter exceeds or drops below anacceptable drive parameter, Processor 58 may output the indication ofclamping failure on the user interface. In response to detection ofclamping failure, Processor 58 may also command additional functions,such as suspending driving of the motor, preventing firing of thestaple, maintaining the clamping force at the point of detected clampingfailure, waiting for user input, and unclamping the tissue. Similarly,the Processor 58 continuously monitors the drive parameter during firingof a staple through successfully clamped tissue. In response to thedrive parameter falling outside the acceptable range of desired driveparameters, Processor 58 may output a failure indication on the userinterface. In response to detected firing failure, Processor 58 maycommand one or more other functions, such as terminating firing or afiring sequence, terminating deployment of the knife blade to cut targettissue, suspending driving of the motor, maintaining clamping of thetissue while preventing firing, or waiting for user input. Processor 58may monitor the drive parameter during a single action, such as thefiring of a single staple, or may continue to monitor the driveparameter throughout a surgical process such as a firing sequence inwhich a plurality of staples are deployed and tissue between stapledareas is cut.

One of skill in the art would appreciate that an indication of clampingfailure may include an indication of how likely clamping failure may be.For example, the Processor 58 may output an indication of clampingfailure indicating the likelihood of clamping failure from a 0% chanceof failure to a 100% chance of failure, thus allowing the user to adjustor terminate the procedure before actual failure occurs based on anincrease in the likelihood of failure as indicated by the failureindication. In some embodiments, if the monitored drive parameter iswithin the acceptable range of drive parameters, then a failureindicator that express a likelihood of failure may express a likelihoodof failure that falls within a range of 0 to 49%. In another embodiment,this range may be expressed as a gradient, including a non-numericalgradient, such as a color gradient. Depending on the likelihood offailure as communicated by the failure indicator, the Surgeon may thensafely proceed with clamping of the body tissue or may abort clampingand reposition the jaws until Display 60 indicates a higher likelihoodof clamping or firing success.

FIGS. 5A and 5B show a Patient Side Cart 22 and a surgical tool 62,respectively. The surgical tool 62, one of the surgical tools 26, is anexample of an end effector having a set of jaw members for clamping atissue and firing a staple into the clamped tissue. The Patient SideCart 22 shown provides for the manipulation of three surgical tools 26and an imaging device 28, such as a stereoscopic endoscope used for thecapture of images of the site of the procedure. Manipulation is providedby robotic mechanisms having a number of robotic joints. The imagingdevice 28 and the surgical tools 26 can be positioned and manipulatedthrough incisions in the patient so that a kinematic remote center ismaintained at the incision so as to minimize the size of the incision.Images of the surgical site can include images of the distal ends of thesurgical tools 26 when they are positioned within the field-of-view ofthe imaging device 28.

Tissue Clamping and Staple Firing With Independent Actuation Mechanisms

In accordance with the present teachings, some exemplary embodimentsutilize two independent actuation mechanisms to control the articulationof an articulated jaw of an end effector. A first actuation mechanismcan be used to provide a high force clamping mode, and a secondactuation mechanism can be used to provide a high force firing mode. Inmany embodiments, the first and second actuation mechanism used toprovide the high clamping force and high firing force isnon-back-drivable. The first and second actuation mechanisms maycomprise a first and a second lead screw. Using independent actuationmechanisms may be beneficial in some surgical applications, for example,electrocautery sealing, stapling, etc., which may require differentforces for different functions during the same procedure.

In various exemplary embodiments disclosed herein, actuation of the jawsin the high clamping force mode is provided by a lead screw actuationmechanism that includes a lead screw driven cam. The driven caminterfaces with a mating cam surface on the articulated jaw so as tohold the articulated jaw in a closed (clamped) configuration when thelead screw driven cam is at a first end of its range of motion. Inaddition, the driven cam does not constrain motion of the articulatedjaw when the lead screw driven cam is at a second end (opposite end) ofits range of motion. In other words, the mating cam surfaces arearranged such that motion of the lead screw driven cam in one directionwill cause the articulated jaw to close, and motion of the lead screwdriven cam in the reverse direction will allow (but not force) thearticulated jaw to open to a limit provided by the cam surfaces. Often,the lead screw actuation mechanism is non-back-drivable. In manyembodiments, the position of the jaw members of the end effector can bedetermined by the position of the cable actuation mechanism, or ifdriven by a lead screw, the position of the lead screw. The system mayinclude a dual drive actuator having a drive for effecting clamping at aclamping force and a drive for effecting firing a staple at a firingforce. The actuator may utilize an existing motor or drive, or utilizean additional drive or motor, to effect firing of the staple. Theclaimed methods and systems monitor the drive parameter of whichevermotor, or motors, which are driving the clamping or firing.Additionally, terminating or stopping driving of the motor when failureis detected may also comprise continuing driving of another drive ormotor affecting another function. For example, if firing failure isindicated, the system may stop driving the firing force, while stillmaintaining the driving of the clamping force and wait for a user tounclamp the tissue.

FIG. 6A is a perspective view of an end effector 70 having a jaw 72articulated by two independent actuation mechanisms, in accordance withmany embodiments. The end effector 70 includes an end effector base 74,the articulated jaw 72, and a detachable stationary jaw 76 (an attachedremovably mountable cartridge), which holds the staples. The endeffector 70 is actuated via a first drive shaft 78, a second drive shaft80, and two actuation cables (not shown). The first drive shaft 78rotates a lead screw 82 of a lead screw actuation mechanism, the leadscrew 82 located within the stationary jaw 76. The second drive shaft 80rotates another lead screw (not shown) of the detachable stationary jaw76.

In many embodiments, the first drive shaft 78 and/or the second driveshaft 80 are driven by drive features located in a proximal tool chassisto which the end effector 70 is coupled with via an instrument shaft. Inmany embodiments, the proximal tool chassis is configured to bereleasably mountable to a robotic tool manipulator. In many embodiments,the first drive shaft 78 and the second drive shaft 80 are actuated viarespective drive features located in the proximal tool chassis. In manyembodiments, such drive features are driven by motors that are locatedin the proximal tool chassis.

FIG. 6B is a perspective view of the end effector 70 of FIG. 6A (withthe articulated jaw 72 removed to better illustrate components of thelead screw actuation mechanism and the stationary jaw/staple cartridge76), in accordance with many embodiments. The lead screw 82 is mountedfor rotation relative to the end effector base 74. A lead screw drivencam 84 is coupled with the lead screw 82 so that selective rotation ofthe lead screw 82 can be used to selectively translate the lead screwdriven cam 84 along a cam slot 86 in the end effector base 74. The endeffector 70 includes a pivot pin 88 that is used to rotationally couplethe articulated jaw 72 with the end effector base 74.

The stationary jaw/staple cartridge 76 acts as a lower jaw of the endeffector or is attached to a lower jaw of an end effector. An upper jaw,such as articulated jaw 72, is positioned above an upper surface ofstaple cartridge 76. Staple cartridge 76 has a proximal end 75 that isattached to the base 74 of the end effector and a distal end 77 disposedat a corresponding distal end of the end effector. The upper surface ofcartridge 76 includes four or six rows of staple openings 79, alongitudinal slot 81, a proximal knife garage 83, a distal knife garage85, and a rotational input (not shown). In many embodiments, a staple isdisposed in each of the staple openings for deployment therefrom. Adrive member (not shown) positioned within the body of cartridge 76 andmounted on or connected to a lead screw (not shown) is movable in adistal direction within the cartridge 76 to dispense the staples,pushing the staples up through the openings 79, through tissue clampedbetween the staple cartridge 76 and articulated jaw 72, into articulatedjaw 72 such that contact with jaw 72 causes the staples to close orfasten to the tissue.

The longitudinal slot 81 accommodates a cutting blade of a knife member(not shown) extending therefrom as the knife member is moved from theproximal knife garage 83 to the distal knife garage 85. In operation, anactuator of the surgical instrument, such as a surgical stapler or arobotic surgical stapler, is drivingly coupled to a rotary input of thecartridge 76 and applies a rotational force or torque to the rotaryinput of the cartridge 76, causing actuation of the lead screw andmovement of the drive member from a proximal end to a distal end of thecartridge 76. Movement of the drive member initiates deployment of thestaples starting at the cartridge proximal end 75 and proceeding to thecartridge distal end 77. The knife blade or cutting blade is deployedafter stapler firing actuation begins, moving from the proximal knifegarage to the distal knife garage. Movement of the knife blade lagsbehind and follows the deployment of staples, such that the knife bladeremains substantially stationary until the lead screw has caused thedrive member to travel a sufficient distance to begin forming anddeploying the staples. The lag distance between firing actuation (stapledeployment) and knife blade movement causes the cut line to trail thestapling of the tissue to ensure that only fully stapled tissue is cut(i.e., minimizes the risk of cutting unstapled tissue). A sensor forsensing, e.g., measuring, the rotary output of the surgical instrumentmay be communicatively coupled to a processor and provide a signalindicative of the output of the surgical instrument to the processor forcontrolling a firing sequence of the surgical stapler instrument.

FIGS. 7A-10 illustrate the actuation mechanisms by which an end effectorclamps a body tissue between its jaws clamping mode and fires a stapleinto the clamped tissue.

FIGS. 7A and 7B illustrate an example of a lead screw actuationmechanism to be used with an end effector having the structure shown inFIGS. 6A and 6B. The lead screw 82 has a distal journal surface 96 and aproximal journal surface that interfaces with a proximal bearing 98. Inmany embodiments, the distal journal surface 96 is received within acylindrical receptacle located at the distal end of the cam slot 86.Such a distal support for the lead screw 82 can be configured to keepthe lead screw 82 from swinging excessively, and with relatively largeclearance(s) between the distal journal surface 96 and the cylindricalreceptacle. The proximal bearing 98 is supported by the end effectorbase 74 so as to support the proximal end of the lead screw 82. Theproximal bearing 98 can be a ball bearing, which may help to reducefriction and wear. A distal bearing (not shown) can be supported by theend effector base 74 so as to support the distal end of the lead screw82, and the distal bearing can be a ball bearing. The lead screw drivencam 84 includes a threaded bore configured to mate with the externalthreads of the lead screw 82. The lead screw driven cam 84 includes topand bottom surfaces configured to interact with corresponding top andbottom surfaces of the cam slot 86. The interaction between lead screwdriven cam 84 and the cam slot 86 prevents the lead screw driven cam 84from rotating relative to the cam slot 86, which causes the lead screwdriven cam 84 to translate along the cam slot 86 in response to rotationof the lead screw.

The articulated jaw 72 includes mating cam surfaces 94 that areconfigured so that the position of the lead screw driven cam 84 alongthe cam slot 86 determines the extent to which the rotational motion ofthe articulated jaw 72 around the pivot pin 88 is constrained by thelead screw driven cam 84. The articulated jaw 72 includes a firstproximal side 100 and a second proximal side 102 that are separated by acentral slot. The first and second proximal sides are disposed onopposing sides of the end effector base 74 when the articulated jaw 72is coupled with the end effector base 74 via the pivot pin 88. Each ofthe first and second proximal sides 100, 102 includes a recessed areadefining a mating cam surface 94 and providing clearance between thelead screw driven cam 84 and the proximal sides 100, 102. When the leadscrew driven cam 84 is positioned at or near the proximal end of the camslot 86 (near its position illustrated in FIGS. 7A and 7B), contactbetween the lead screw driven cam 84 and the mating cam surfaces 94 ofthe articulated jaw 72 hold the articulated jaw in a clampedconfiguration. When the lead screw driven cam 84 is positioned at thedistal end of the cam slot 86, the rotational position of thearticulated jaw around the pivot pin 88 is unconstrained by the leadscrew driven cam 84 for a range of rotational positions between aclamped configuration (where there is a gap between the lead screwdriven cam 84 and the mating cam surfaces 94 of the articulated jaw 72)and an open configuration (where there may or may not be a gap betweenthe lead screw driven cam 84 and the mating cam surfaces 94 of thearticulated jaw 72). For positions of the lead screw driven cam 84 inbetween the proximal and distal ends of the cam slot 86, the range ofunconstrained motion can vary according to the cam surfaces used.

The use of a recess in each of the proximal sides 100, 102 to define themating cam surfaces 94 of the articulated jaw 72 provides a number ofbenefits. For example, the use of recesses as opposed to traverse slotsthat extend through the proximal sides provides a continuous outsidesurface to the proximal sides 100, 102 of the articulated jaw, which isless likely to snag on patient tissue than would a traverse slotopening. The absence of traverse slots also helps to stiffen theproximal sides 100, 102 as compared to proximal sides with traverseslots, and therefore provides increased clamping stiffness. Suchproximal sides 100, 102 may have increased stiffness in two planes,which may help maintain alignment of the articulated jaw 72 in thepresences of external forces. Such increased stiffness in two planes maybe beneficial in some surgical applications, for example, in tissuestapling where it is beneficial to maintain alignment between thestaples and anvil pockets that form the staples. Further, the use ofrecesses instead of traverse slots also provides an actuation mechanismthat is less likely to be jammed by extraneous material as compared toone having proximal sides with open traverse slots.

The lead screw actuation mechanism can be configured to provide adesired clamping force between the articulated jaw and an opposing jawof the end effector to facilitate cutting or sealing of the tissue. Forexample, in many embodiments, the lead screw actuation mechanism isconfigured to provide at least 20 pounds of clamping force at the tip ofthe articulated jaw 72 (approximately 2 inches from the pivot pin 88).In many embodiments, the lead screw actuation mechanism is configured toprovide at least 50 pounds of clamping force at the tip of thearticulated jaw 72. In many embodiments, to produce 50 pounds ofclamping force at the tip of the articulated jaw 72, the input torque tothe lead screw 82 is approximately 0.1 Newton meters and the lead screw82 has 33 turns. The system may detect the displacement of the motor, ofthe clamping or firing mechanism or the configuration of the endeffector by sensing the displacement of the lead screw. For example, inmany embodiments, the system is calibrated before starting the procedureso as to determine the range of motion of both the clamping and thefiring mechanism and the displacement of the lead screw within thatrange of motion. Such calibration allows the system to determine theconfiguration of the end effector or the displacement of the mechanismsolely from the displacement of the lead screw.

The lead screw actuation mechanism can be fabricated using availablematerials and components. For example, many components of the lead screwactuation mechanism can be fabricated from an available stainlesssteel). The lead screw driven cam 84 can be coated (e.g., TiN) to reducefriction against the surfaces it rubs against (e.g., lead screw 82; endeffector base 74; proximal sides 100, 102 of the articulated jaw 72).Stranded cables can be used to drive the first actuation mechanism.

FIGS. 8A through 8F illustrate components of a cable actuation mechanism110, in accordance with many embodiments. As described above, the leadscrew driven cam 84 can be positioned at the distal end of the cam slot86 (i.e., near the pivot pin 88). For such a distal position of the leadscrew driven cam 84, as discussed above, the rotational position of thearticulated jaw 72 about the pivot pin 88 is unconstrained for a rangeof rotational positions of the articulated jaw 72. Accordingly, therotational position of the articulated jaw 72 about the pivot pin 88 canbe controlled by the cable actuation mechanism 110. The cable actuationmechanism 110 is operable to vary the rotational position of thearticulated jaw between the clamped configuration and the openconfiguration. The cable actuation mechanism 110 includes a pair of pullcables 112, 114. The cable actuation mechanism 110 also includes a firstlinkage 116 that is used to rotate the articulated jaw 72 about thepivot pin 88 towards the clamped configuration, and an analogous secondlinkage 118 that is used to rotate the articulated jaw 72 about thepivot pin 88 towards the open configuration. The first linkage 116(shown in FIGS. 8A and 8B) includes a rotary link 120 that is mountedfor rotation relative to the end effector base 74 via a pivot pin 122. Aconnecting link 124 couples the rotary link 120 to the articulated jaw72 via a pivot pin 126 and a pivot pin 128. The first linkage 116 isarticulated via a pulling motion of the pull cable 112. In operation, apulling motion of the pull cable 112 rotates the rotary link 120 in aclockwise direction about the pivot pin 122. The resulting motion of theconnecting link 124 rotates the articulated jaw 72 in acounter-clockwise direction about the pivot pin 88 towards the clampedconfiguration.

The second linkage 118 (shown in FIGS. 8C through 8F) of the cableactuation mechanism 110 includes analogous components to the firstlinkage 116, for example, a rotary link 130 mounted for rotationrelative to the end effector base 74 via a pivot pin 132, and aconnecting link 134 that couples the rotary link 130 to the articulatedjaw 72 via two pivot pins 136, 138. The second linkage 118 isarticulated via a pulling motion of the pull cable 114. The secondlinkage 118 is configured such that a pulling motion of the pull cable114 rotates the articulated jaw 72 about the pivot pin 88 towards theopen configuration. In many embodiments, the pivot pin 136 between theconnecting link 134 and the rotary link 130 of the second linkage 118 is180 degrees out of phase with the pivot pin 126 between the connectinglink 124 and the rotary link 120 of the first linkage 116. Coordinatedpulling and extension of the pull cables 112, 114 of the cable actuationmechanism 110 is used to articulate the articulated jaw 72 between theopen and clamped configurations. In order to best provide equal andopposite cable motion (and thereby maintain cable tension in acapstan-driven system described below), a common rotational axis for thepivot pins 122, 132 is configured to lie on a plane that contains therotational axes for pivot pins 128, 138 when the articulated jaw 72 isclosed (or nearly closed) and again when the when the articulated jaw 72is open (or nearly open). The connecting links 124, 134 are assembledsymmetrically opposite about this same plane for the first and secondlinkages 116, 118. The distance between the pivot pins 122, 126 andbetween the pivot pins 132, 136 is the same for both the first andsecond linkages 116, 118, and the distance between the pivot pins 126,128 and between the pivot pins 136, 138 is the same for both the firstand second linkages 116, 118.

FIGS. 9A and 9B illustrate an articulation of the articulated jaw 72 viaanother cable actuation mechanism 140, in accordance with manyembodiments. In embodiment 140 of the cable actuation mechanism, a firstpull cable 142 and a second pull cable 144 are directly coupled with theproximal end of the articulated jaw 72. The first pull cable 142 wrapsaround a first pulley 146 so that a pulling motion of the first pullcable 142 rotates the articulated jaw 72 about the pivot pin 88 towardsthe clamped configuration. The second pull cable 144 wraps around asecond pulley 148 so that a pulling motion of the second pull cable 144rotates the articulated jaw 72 about the pivot pin 88 towards the openconfiguration. Accordingly, coordinated pulling and extension of thefirst and second pull cables of the cable actuation mechanism 140 isused to articulate the articulated jaw 72 between the open and clampedconfigurations. In order to best provide equal and opposite cable motion(and thereby maintain cable tension in the capstan-driven systemdescribed below), the radius of the arc prescribed by cable 142 aboutthe pivot 88 is substantially the same as the radius prescribed by cable144 about the pivot 88.

Although the mechanisms may comprise lead screws, cables, or hypotubes,alternate mechanisms can be used to effect clamping or staple firing.For example, an actuation mechanism comprising push/pull rods or springscan be used.

FIG. 10 is a cross-sectional view illustrating components of the abovediscussed lead screw actuation mechanism. The illustrated componentsinclude the lead screw 82, the lead screw driven cam 84, the cam slot 86in the end effector base 74, the distal journal surface 96, thecylindrical receptacle 154 in the end effector base, and the proximalbearing 98 supported by the end effector base 74.

FIG. 11 is a simplified diagrammatic illustration of a tool assembly170, in accordance with many embodiments. The tool assembly 170 includesa proximal actuation mechanism 172, an elongate shaft 174 having aproximal end and a distal end, a tool body 176 disposed at the distalend of the shaft, a jaw 178 movable relative to the tool body 176between a clamped configuration and an open configuration, a firstactuation mechanism coupled with the jaw, and a second actuationmechanism coupled with the jaw. The first actuation mechanism isoperable to vary the position of the jaw relative to the tool bodybetween the clamped configuration and the open configuration. The secondactuation mechanism has a first configuration where the jaw is held inthe clamped configuration and a second configuration where the positionof the jaw relative to the tool body is unconstrained by the secondactuation mechanism. The first actuation mechanism is operativelycoupled with the proximal actuation mechanism. In many embodiments, thefirst actuation mechanism comprises a pair of pull cables that areactuated by the proximal actuation mechanism. The second actuationmechanism is operatively coupled with the proximal actuation mechanism.In many embodiments, the second actuation mechanism includes a leadscrew driven cam located in the tool body that is driven by the proximalactuation mechanism via a drive shaft extending through the elongateshaft 174 from the proximal actuation mechanism.

The tool assembly 170 can be configured for use in a variety ofapplications. For example, the tool assembly 170 can be configured as ahand held device with manual and/or automated actuation used in theproximal actuation mechanism. The tool assembly 170 can also beconfigured for use in surgical applications, for example, electrocauterysealing, stapling, etc. The tool assembly 170 can have applicationsbeyond minimally invasive robotic surgery, for example, non-roboticminimally invasive surgery, non-minimally invasive robotic surgery,non-robotic non-minimally invasive surgery, as well as otherapplications where the use of the disclosed redundant jaw actuationwould be beneficial.

Redundant jaw actuation can be used to articulate a jaw of a robotictool end effector. For example, FIG. 12 schematically illustrates arobotic tool 180 employing redundant jaw actuation. The robotic tool 180includes a proximal tool chassis 182, a drive motor 184, an instrumentshaft 186, a distal end effector 188, a first actuation mechanismportion 190, and a second actuation mechanism 192. The distal endeffector 188 comprises an articulated jaw 194. The proximal tool chassis182 is releasably mountable to a robotic tool manipulator 196 having afirst drive 198, and a first actuation mechanism portion 200 thatoperatively couples with the first actuation mechanism portion 190 ofthe robotic tool 180 when the proximal tool chassis 182 is mounted tothe robotic tool manipulator 196. The instrument shaft 186 has aproximal end adjacent the tool chassis 182, and a distal end adjacentthe end effector 188. The first actuation mechanism (comprising portion200 and portion 190) couples the first drive 198 to the articulated jaw194 when the tool chassis 182 is mounted to the tool manipulator 196 soas to articulate the end effector 188 between an open configuration anda clamped configuration. The second actuation mechanism 192 couples thedrive motor 184 to the articulated jaw 194 so as to apply a firing forceto a staple so as to fire the staple from the end effector through thetissue clamped within the jaws of the end effector. The first actuationmechanism can be a lead screw-driven mechanism that provides relativelyhigh forces so as to fire the staple through the tissue. The secondactuation mechanism can include a drive shaft that couples the drivemotor 184 with a lead screw actuation mechanism, for example, an abovediscussed lead screw actuation mechanism that provides the high clampingforce mode. System 180 includes Sensor 193 for monitoring the driveparameters of the first drive 198 and the drive motor 184 duringclamping and firing, respectively. Sensor 193 may also detect thedisplacement of the first drive and the drive motor so as to determinethe acceptable range of desired drive parameters according to a givendisplacement of the motor or configuration of the end effector. Theconfigurations of the end effector in a clamping mode may include anopen configuration, a close/clamped configuration and any configurationtherebetween. The configurations of the end effector in the firing modemay include a pre-firing configuration in which one or more staples aredisposed within the end effector and releasably coupled with the drivemotor 184 through a mechanism and a post-firing configuration where oneor more staples have been fired through the tissue, and typically bentso as to seal the tissue, the staple having been released from the endeffector. The configurations of the end effector may also include anyconfiguration in between the pre-firing and post-firing mode. Bydetecting the displacement of the first drive or drive motor, the sensorcan determine a given configuration of the end effector in either mode,so as to more accurately determine the acceptable range of drivingparameters and predict failure of clamping or firing.

In accordance with the present teachings, the firing force for formingstaples is approximately 1.5-2.0 pounds, however, the staple cartridgeconstruction allows between two (2) and (6) staples to be fired (and indoing so, causing them to be formed) simultaneously. Thus, for a staplecartridge intended to fire two (2) staples, an expected actuation/firingforce would be approximately 3.0-4.0 pounds, while for a staplecartridge intended to fire six (6) staples at a time, the expectedinitial actuation/firing force to be approximately 9-12 pounds. (Itshould be noted that these forces are approximate and are not indicativeof the input force which may be delivered via any number of mechanicalmeans, i.e. linear motion(push/pull), rotary motion, etc.) In a casewhere, during initial actuation of the firing sequence staples are notbeing formed due to staples missing from a staple cartridge, the initialactuation force required would be low because it would move only thedrive member (staples would not be encountered, pushed, and formed)through the cartridge, requiring a force of about less than 1 pound.Such an initial actuation force would be significantly lower than theexpected value of about 4 pounds or about 10 pounds (depending oncartridge size and type), and when a force lower than the expectedminimum (minimum threshold) is sensed, the Processor would identify thelow force as a stapler misfire or failure. As discussed below, theProcessor may, in such a case, terminate a stapling sequence, and mayfurther provide a warning to the user of the misfire or failure.

Continued monitoring of the staple actuation force after initialactuation would consider whether the actuation force remains within anacceptable range of forces, with a lower end of the range indicating anempty cartridge and an upper end of the range representing a potentiallyjammed stapler or a stapler encounter a material too tough to bestapled. During the continued monitoring phase, the Processor wouldidentify potential problems with the stapling sequence if the actuationforce fell below a minimum force of approximately 2 pounds or 5 pounds,depending on the size and type of the staple cartridge, or if theactuation force exceeded a maximum force (maximum threshold) ofapproximately 6-8 pounds or 15-20 pounds, depending on the size and typeof the staple cartridge.

According to an exemplary embodiment of the present teachings, theProcessor continuously compares a measured actuation force applied tothe staple cartridge (Tmeas) to a minimum threshold force (Tmin) and amaximum threshold force (Tmax) throughout the staple firing sequence.FIG. 16C illustrates an exemplary measured actuation force, or torque,applied to a staple cartridge during a successful staple firingsequence. As illustrated, the measured torque Tmeas remains above theminimum threshold force Tmin and below the maximum threshold force Tmax.

FIG. 13 is a diagrammatic view of a telerobotic surgical system whichincorporates an embodiment of the present teachings. In the example ofFIG. 13, a physician inputs a command to the system to clamp a tissue orfire a staple. In response to the user command, the system beginsdriving the motor 210 so as to drive clamping or firing through theclamping and/or firing mechanism 240. As mechanism 240 effects clampingor firing, Processor 220 monitors a drive parameter, such a torqueoutput, of Motor 210. Monitoring may comprise comparing the torqueoutput to an acceptable range of torque outputs for a given displacementand/or velocity of the motor or mechanism. The Processor 220 may becoupled to any or all of the Motor 210, the Mechanism 240 or a Sensor230 for detecting a displacement of the motor or mechanism during theclamping or firing. In response to the monitored drive parameter fallingoutside an acceptable range of torque outputs (or displacements of thedriving mechanism), Processor 220 outputs a Failure Indication 250 onDisplay 60 of the user interface, indicating that clamping or firing hasfailed, or a likelihood of failure. Typically, Display 60 includesimages of the end effector during clamping or firing.

In an exemplary embodiment, Processor 220 may run an algorithm, storedon a memory or other computer-readable storage medium (not shown) thatmonitors the firing force or torque applied by the telerobotic surgicalsystem. The Processor 220 will stop the staple firing sequence if thefiring force or torque is below a threshold force value, indicative ofcartridge misfire or the failure to deploy staples. Similarly, theProcessor 220 will stop the staple firing sequence if the firing forceor torque is above a second threshold force value, indicative of jammingin the stapler. By monitoring the firing force, and most particularly aninitial firing force, Processor 220 may be able to prevent tissuedamage. For example, when a firing force is indicative of failure todeploy staples, terminating the firing sequence will reduce thepossibility that unstapled tissue will be cut by a knife deployed by thestaple cartridge. At the beginning of a cutting sequence, there may be aslight delay between the time the stapler deploys staples and the knifeblade begins to cut the stapled tissue. This delay may be attributableto the time necessary to form staples before stapling the tissue. Oncethere is an indication that a force necessary to properly form anddeploy staples is not present, Processor 220 aborts the firing andcutting sequence. Although discussed with respect to the initiation of afiring and cutting sequence, Processor 220 may monitor the firing forcethroughout an entire firing and cutting sequence, and control theprocess by terminating the process if the firing force drops below thefirst threshold value or rises above the second threshold value.

Processor 220 receives a signal indicative of an initial actuation forceapplied to staple cartridge 76. Processor 220 compares the initialactuation force to a threshold value, for example a lower thresholdvalue, and controls the firing and cutting sequence based on thecomparison. If the initial action force is less than the lower thresholdvalue, then the Processor 220 terminates the staple firing and cuttingsequence. An initial actuation force less than the lower threshold valueis indicative that staples are not being formed or deployed properly,and termination of the sequence may prevent tissue damage in the form oftissue being cut without first being stapled. If the actuation force isgreater than the lower threshold value, then Processor 220 may permitthe firing and cutting sequence to continue. Processor 220 may continueto monitor and the actuation force applied to the staple cartridge andcompare the actuation force to the lower threshold value and also to anupper threshold value. If the actuation force is greater than the upperthreshold value, Processor 220 may terminate the firing and cuttingsequence. An actuation force greater than the upper threshold value isindicative of a jam in the staple firing mechanism, and termination ofthe sequence can prevent burnout of the motor or other problems with theinstrument, as well as prevent tissue damage. Processor 220 may outputto a user interface an indication of determinations to terminate thefiring and cutting sequence or to permit the sequence to continue. Suchoutputs to the user interface may take the form of warnings to the user,as discussed below.

FIGS. 14A-14B illustrate two examples of failure indicator 250 that mayappear on Display 60 of System 10. Typically, the user interface Display60 depicts images and/or visual representations of the surgical tool endeffectors during the surgery in addition to the indicators of clampingor firing failure. The failure indicator may be superimposed over theimages on the user interface display during the surgical procedure so asto seamlessly incorporate the features of the present teachings into thesurgical procedure. Preferably, the failure indicator only appears whenthe Surgeon has commanded System 10 to clamp or fire a staple into aclamped tissue. By monitoring the drive parameter, System 10 provides anindication of failure during the procedure. FIG. 14A depicts Display 60with a clamping failure indicator 250 superimposed on the lower rightarea of the screen, wherein the failure indicator 250 indicates thatclamping success is likely and that the system is proceeding to clamp.FIG. 14B depicts Display 60 with failure indicator 250 superimposed onthe lower right area of the screen, wherein the indicator indicates thatclamping will likely fail. Failure indicator 250 is output in responseto the monitored drive parameter driving the clamping being outside thepredetermined range of acceptable drive parameters.

FIG. 15A-15B illustrate additional examples of the clamping predictionindicator 250. FIG. 15A depicts an example of a failure indicatorshowing a likelihood of clamping failure as a gradient, where in thisexample, the likelihood is expressed as a percentage of chance. Forexample, the further outside the range of predetermined drive parametersthe actual monitored drive parameter is, the more likely clampingfailure will be. For example, in one embodiment, if the actual monitoreddriving torque is within 5% of a predetermined target driving torque,the system will display an indicator of 90% likelihood of clampingsuccess. As the monitored driving torque further diverges from thetarget driving torque, the likelihood decreases in a monotonicrelationship, such as from 90% down to a 0% likelihood of clamping.Alternatively, the driving parameter may be the displacement of thedriving mechanism. In such an embodiment, the system may monitor thedisplacement of the driving mechanism and indicate clamping or firingfailure when the displacement is outside a predetermined range ofacceptable displacements. FIG. 15B depicts an embodiment having anindicator which toggles between two settings. When the light of theindicator is lit, likely firing failure is indicated, otherwise firingfailure is not indicated.

FIGS. 16A-16C illustrate graphs of a monitored drive parameter inrelation to an acceptable range of desired drive parameters, inaccordance with many exemplary embodiments of the present teachings.This embodiment illustrates that the system may provide an indication ofclamping and/or firing failure simply from monitoring the torque of themotor as it drives the clamping or firing of the system. As shown, thepredetermined range of torques may vary in relation to the displacementof the motor as it effects movement of the end effector. Thedisplacement (s) of the motor may be correlated by the system to aposition of the end effector during the clamping process. For example,during clamping, as the displacement of the motor moves from S_(i) toS_(f), the jaws of the end effector move from an open configuration to aclosed (clamped) configuration. Similarly, the motor displacement may beused to track the position or configuration of the end effector duringfiring of a staple into the clamped tissue. In many embodiments, beforeperforming a procedure, the system calibrates the jaws of the endeffector from a first to a second configuration, such as calibratingjaws from an open position to a closed position, so as to correlate thedisplacement of the motor with the configuration of the end effector.

FIG. 16A illustrates a predetermined range of acceptable driving torques(t) which vary with motor displacement(s). The range is delimited by twofunctions, an upper boundary t_(upper) and a lower boundary t_(lower).The system outputs an indication of clamping failure in response to themonitored driving torque T as compared to the predetermined range ofacceptable driving torques. If the displacement of the motor reaches Sfand the system has not indicated likely clamping or firing failure, thesystem may provide an indication of successful clamping or firing. Inthis example, the graph depicts the acceptable range of torques and themonitored driving torque during clamping as T1. As shown, during theclamping, T1 remains within the acceptable range of driving torques,thus the system would output an indication that clamping is likelysuccessful (which may include a lack of an indication of failure).

FIG. 16B illustrates a similar predetermined range of acceptable drivingtorques (t) and two separate driving torques, T2 and T3 (occurring atdifferent times). As shown, T2 falls below the lower boundary,t_(lower), of the acceptable range of torques. This may occur where thetissue has slipped out of the jaws of the end effector and less torqueis required to close the jaws since there is no tissue between the jaws.Alternatively, this situation may occur, for example, where thecartridge does not include staples (e.g., a previously used cartridge isloaded in the stapler) or is missing other items. In such case, thesystem would output an indication of likely clamping failure at FailurePoint F2, at which point the system may suspend driving of the clampingto prevent any possible tissue damage from continuing to apply theclamping force after failure occurs. Failure may also occur if thedriving torque exceeds the upper boundary of the range of acceptabletorques, as shown by monitored torque T3. This may occur where jaws haveclamped onto a bone and an excessive amount of torque is required toreach the closed/clamped configuration, which may potentially causetissue damage to the bone or surrounding tissue. This might also occurwhen a staple is jammed. In this example, the monitored torque exceedst_(upper) at Failure Point F3, at which point the system may suspenddriving of the clamping or firing to reduce the likelihood of tissuedamage. In response to detection of failure, the system may suspenddriving of the drive parameter or reverse the driving force to unclampthe tissue, in addition to providing an indication of failure.

FIG. 16C illustrates a predetermined range of acceptable driving torques(t) which vary with motor displacement(s). The range is delimited by twofunctions, an upper boundary Tmax and a lower boundary Tmin. The systemoutputs an indication of firing failure in response to the monitoreddriving torque Tmeas as compared to the predetermined range ofacceptable driving torques. In this example, the graph depicts theacceptable range of torques and the monitored driving torque duringfiring as Tmeas. As shown, during the firing, Tmeas remains within theacceptable range of driving torques, thus the system would output anindication that firing is likely successful (which may include a lack ofan indication of failure).

FIGS. 17-19 graphically illustrate embodiments of the claimed methods.FIG. 17 is a simplified representation of exemplary method 300. Method300 includes a step 302 of monitoring a drive parameter of a motordriving a tool to clamp and a step 304 of outputting an indication on auser interface of a likelihood of clamping failure during clamping inresponse to the monitored drive parameter. FIG. 18 is a simplifiedrepresentation of exemplary method 304. Method 304 includes a step 305of monitoring a drive parameter of a motor driving a tool to fire astaple into a clamped material and a step 307 of outputting anindication on a user interface of a likelihood of firing failure duringfiring in response to the monitored drive parameter. FIG. 19 is asimplified representation of a method 310 which further includes thestep 312 of driving a motor to clamp a tissue in response to a userinput to clamp, a step 314 of monitoring a drive parameter of the motorduring clamping of the tissue, a step 316 of outputting an indication ofa likelihood of clamping failure during clamping in response to themonitored drive parameter, and a step 318 of suspending driving of themotor if there is an indication of likely failure or continuing drivingof the motor if there is no indication of likely failure. FIG. 20 is asimplified representation of a method 320 which includes step 322 ofdriving a motor to clamp or fire a staple into a clamped material inresponse to a user input, step 324 of monitoring a drive parameterduring clamping or firing, step 326 of outputting an indication on auser interface of the likelihood of clamping or firing failure duringclamping or firing. If there is no indication of likely failure, thenthe method of 320 further includes step 328 of continuing driving themotor to clamp or fire and step 330 of outputting a message of successwhen clamping or firing complete. If there is an indication of likelyfailure, then the method of 320 further includes step 332 of suspendingdriving of the motor in response to the indication and step 334 ofoutputting an indication that the driving parameter has been suspended.

FIGS. 21-22 depict flowcharts illustrating embodiments of the claimedmethods. FIG. 21 is a flow chart showing an embodiment of the claimedmethod as applied to clamping as it would be incorporated into aminimally invasive robotic surgical system. FIG. 22 is a flow chartshowing an embodiment of the claimed method as applied to firing of astaple into clamped tissue as it would be incorporated into the roboticsurgical system of FIG. 20. The described robotic system may requireuser input to command the system to clamp and/or firing the staple intothe clamped tissue.

Further modifications and alternative embodiments will be apparent tothose of ordinary skill in the art in view of the disclosure herein. Forexample, the systems and the methods may include additional componentsor steps that were omitted from the diagrams and description for clarityof operation. Accordingly, this description is to be construed asillustrative only and is for the purpose of teaching those skilled inthe art the general manner of carrying out the present teachings. It isto be understood that the various embodiments shown and described hereinare to be taken as exemplary. Elements and materials, and arrangementsof those elements and materials, may be substituted for thoseillustrated and described herein, parts and processes may be reversed,and certain features of the present teachings may be utilizedindependently, all as would be apparent to one skilled in the art afterhaving the benefit of the description herein. Changes may be made in theelements described herein without departing from the spirit and scope ofthe present teachings and following claims.

It is to be understood that the particular examples and embodiments setforth herein are nonlimiting, and modifications to structure,dimensions, materials, and methodologies may be made without departingfrom the scope of the present teachings. For example, various aspectshave been described in the context of an instrument used in a surgicalrobotic system. But these aspects may be incorporated into hand-heldinstruments as well.

Other embodiments in accordance with the present disclosure will beapparent to those skilled in the art from consideration of thespecification and practice of the teachings disclosed herein. It isintended that the specification and examples be considered as exemplaryonly, with a true scope and spirit being indicated by the followingclaims.

What is claimed is:
 1. A system, comprising: a surgical instrumentcomprising: an end effector comprising a first jaw and a second jaw, thesecond jaw including a plurality of staples, and an actuation mechanismoperably coupled to at least one of the first jaw and the second jaw ofthe end effector to perform a clamping procedure; a drive systemconfigured to apply an actuation force to the actuation mechanism; and acontroller operably coupled to the drive system, the controllerconfigured to: measure the actuation force applied by the drive systemto the actuation mechanism, and control continued application of theactuation force based on a comparison of the measured actuation force toa threshold value.
 2. The system of claim 1, wherein the controller isfurther configured to terminate the continued application of theactuation force if the measured actuation force is less than thethreshold value.
 3. The system of claim 2, further comprising: a userinterface operably coupled to the controller, the user interface beingconfigured to provide an indication of a clamping procedure failure inresponse to the measured actuation force being less than the thresholdvalue.
 4. The system of claim 3, wherein the user interface is furtherconfigured to provide feedback regarding a risk of failure of theclamping procedure based on a proximity of the measured actuation forceto the threshold value.
 5. The system of claim 3, wherein the userinterface comprises a display configured to output an image of the endeffector during a surgical procedure.
 6. The system of claim 1, furthercomprising a sensor that is operably coupled to the drive system, thesensor being configured to measure the actuation force.
 7. The system ofclaim 1, wherein the end effector further comprises a cutting blade, thecontroller being configured to control actuation of the cutting bladebased on the comparison of the measured actuation force to the thresholdvalue.
 8. The system of claim 7, wherein the controller is configured toterminate the actuation of the cutting blade in response to the measuredactuation force being less than the threshold value.
 9. The system ofclaim 1, wherein the controller is further configured to controlactuation of a staple firing mechanism of the end effector based on thecomparison of the measured actuation force to the threshold value. 10.The system of claim 9, wherein the controller is configured to terminatethe actuation of the staple firing mechanism in response to the measuredactuation force being less than the threshold value.
 11. The system ofclaim 1, wherein: the threshold value is a first threshold value; andthe controller is further configured to: control the continuedapplication of the actuation force based on a comparison of the measuredactuation force to a second threshold value, and terminate the continuedapplication of the actuation force if the measured actuation force isgreater than the second threshold value.
 12. The system of claim 11,further comprising: a user interface operably coupled to the controller,the user interface being configured to provide an indication of aclamping procedure failure in response to the measured actuation forcebeing greater than the second threshold value.
 13. The system of claim12, wherein the user interface is further configured to provide feedbackregarding a risk of failure of the clamping procedure based on aproximity of the measured actuation force to the second threshold value.14. The system of claim 12, wherein the user interface comprises adisplay configured to output an image of the end effector during asurgical procedure.
 15. The system of claim 11, wherein the end effectorfurther comprises a cutting blade, the controller being configured tocontrol actuation of the cutting blade based on the comparison of themeasured actuation force to the second threshold value.
 16. The systemof claim 15, wherein the controller is configured to terminate theactuation of the cutting blade in response to the measured actuationforce being greater than the second threshold value.
 17. The system ofclaim 11, wherein the controller is further configured to controlactuation of a staple firing mechanism of the end effector based on thecomparison of the measured actuation force to the second thresholdvalue.
 18. The system of claim 17, wherein the controller is configuredto terminate the actuation of the staple firing mechanism in response tothe measured actuation force being greater than the second thresholdvalue.
 19. The system of claim 1, wherein: the actuation mechanism is amotor, and the actuation force is a rotational force output by themotor.
 20. The system of claim 1, wherein the second jaw is a stationaryjaw and the first jaw rotates relative to the second jaw in order toperform the clamping procedure.
 21. The system of claim 20, furthercomprising a staple cartridge received by the second jaw, the staplecartridge comprising the plurality of staples.